1. Field of the Invention
The present invention relates to a unisex coupling or a quick disconnect coupling, in which two identical coupling halves can be connected to one another normally by relative rotation therebetween. In particular, the present invention relates to a unisex coupling with a locking mechanism.
2. Description of the Related Art
The ball valved type unisex coupling currently in production utilizes a manually operated ball valve being opened or closed by turning a handle. When two identical halves are connected, an interface seal will be engaged against each other. As the ball valves are open, a flow path will be established through the coupling assembly. Also, while the assemblies are connected and valve opened, a locking mechanism will be actuated by the operating handles so that the two connected coupling halves cannot be disconnected as long as either one of the ball valves remains open.
In the one such unisex coupling currently produced by the Assignee of the present application and disclosed in U.S. Patent Publication No. US 2012/0007007 A1, the entirety of which is incorporated by reference herein, the valve shaft of the coupling has a cam section machined on its outwardly-facing surface. When the valve handle is turned, the cam mechanically drives a number of balls through the coupling body such that a portion of the ball in the far end (away from the cam surface) is driven into the path of the mating half latching lug, securing the mating half in the connected position. As the valve is turned to the closed position, the cam frees the balls to roll back into the valve body either by gravity or compression from the disconnecting turn motion of the mating half, thus freeing the mating half to be disconnected.
The unisex coupling is equipped with an operating handle to open or close the ball valve. The ball valve actuation is accomplished by turning of the handle. This handle features a spring locking mechanism with a plunger. When turned to the selected open or closed position, the spring will push the plunger into a respective slot on the handle boss of the coupling body such that the handle will be locked in the selected position and cannot be inadvertently turned from its selected position.
Unisex couplings of known existing art employ a locking mechanism to address the spillage safety of the coupling in the connected position, and such locking mechanisms prevent inadvertent disconnection of the coupling halves. While known locking mechanisms prevent the two halves from being disconnected unless the ball valves in both connected halves are in the closed position, it is still possible that the ball valve of a disconnected coupling could be mistakenly opened by operating the valve handle. Thus, while known locking mechanisms can provide a secured safety feature to prevent the coupling from being disconnected with a ball valve still in open position, it can only provide limited security to prevent a ball valve from being opened inadvertently when the coupling halves are disconnected. Known locking mechanisms do not prevent a user from unintentionally opening a ball valve, such as by taking the simple steps required to pull and turn the handle, while the coupling is in the disconnected condition. Opening a ball valve while the two halves are disconnected can result in spillage of the coupling's contents and in loss of pressure in the coupling.